which cam with dart iron eagle 200cc heads on my 355 - Third Generation F-Body Message Boards

19doug90 · 09-29-2009, 08:43 PM

This is with their older casting designs not the new platinum design. I cant seem to get any good flow bench numbers for the heads for numbers between .50 and .55

The motor is a bit of a jumble because the shop that built it on the other side of the country (moved last summer) put the wrong heads on it (was supposed to be the 180's).

So i'm having to rebuild the thing using what i have but my cam is destroyed so i'm going to get a new one.

Motor had this in it
CS XR276HR-12
http://www.summitracing.com/parts/CCA-08-503-8/

looking at this
http://www.summitracing.com/parts/CCA-08-432-8/
CS XR282HR-10

Only two concerns with the cam with more duration is i'm not sure if thats going to be too much lift with the 1.6 rockers i have for optimizing my heads.

Also not sure if i'm going to have any braking issues with the lower vacuum levels? car is getting set up for solo1 and solo2.

EDIT: flow number i have say at .50 the numbers are 261/172 and at .60 are 252/174 ugh i'm almost thinking the 1.6's might not work well at all, in which case if i'm getting another set of rockers i almost might as well buy the right heads *rolls eyes*

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Atilla the Fun · 10-01-2009, 12:03 PM

you don't have to use a "shelf" cam, you can custom order one. COMP has lots of lower-lift, long-duration lobes.

19doug90 · 10-01-2009, 12:09 PM

i'm not going custom this motor isnt going to be anything special and with the wrong heads is a bit of a mismatch of parts anyways. It's a stock balanced bottom end so it's not going to be good for a whole hell of a lot of rpm anyways.

More so just wondering if that 282 with such a low LSA is going to be worth messing with on a fuel injected road course car.

Atilla the Fun · 10-01-2009, 12:13 PM

a 200 cc head on a 355 is plenty good as low as 2400 rpm, so you don't need a 282 cam to take advantage of the 200 cc intake ports. in fact, an XE270 cam would be a good match.

19doug90 · 10-01-2009, 12:18 PM

i would have thought that the longer duration would allow for a little bit more time for the cylinders to fill, not to mention the motor would behappier up top as opposed to mid range because i dont have a whole lot of velocity with a small displacement motor and large heads. The 276 with these heads and a 112 lsa made peak around 6, figured something with a lower lsa and a little bit longer duration could be good for a little bit more power. I dont have any issues with shifting at 6k rpms.

Atilla the Fun · 10-01-2009, 12:28 PM

Now it seems to me that you know what you'd like to try, but it could end up being a $400 mistake if it's not what you hope. Is it worth $400 to you to learn? If not, let go of the 10 hp and the curiousity and repeat the known safe combination. But you'll forever be asking yourself "what if". You should be good through 6200 rpm with the XE276HR.

19doug90 · 10-01-2009, 12:34 PM

Quote:

Originally Posted by Atilla the Fun

Now it seems to me that you know what you'd like to try.

lol that obvious eh?

i'm just trying to bounce some idea's around as to whether it's worth trying.

the 276 was plenty good till 6200 cant even remember if it had peaked by 6000 on the dyno on a crappy tune at that, that was on a 112 lsa.

I was looking at that 282 because it has more duration but a lower lsa which would keep power in more or less the same spot with longer duration.

I guess by the same token i should be considering the 276 in a 110 lsa then for the same reason, really wondering with a descent tune if the 110 is going to be liveable on a roadrace car? or if its "lumpyness" is going to be an issue when trying to baby the throttle on the edge of traction going around a corner.

19doug90 · 10-01-2009, 12:37 PM

and on that note there is this cam
http://www.compcams.com/Cam_Specs/Ca...?csid=214&sb=2

lower duration at .050 at a 114 lsa so it'll be smoother and still make power in the same spot, just wondering how much having that bit less of fill time on the duration is going to hurt peak power.

the 276 in a 112 definitely seems to be a happy medium tho.

Atilla the Fun · 10-01-2009, 12:47 PM

If emissions is an issue, the 282 is out. If miles per gallon is an issue, the 114 cam is it. Beyond that, I can't say, since I haven't tried a combination like this in an application like this.

19doug90 · 10-01-2009, 12:57 PM

no emissions, and its a weekend cruiser/solo1 and 2 car so fuel is no concern.

lktna · 10-01-2009, 07:19 PM

MY 355 with the XR288HR and Dart Iron Eagles with 215 intake runners made 325 hp and 335 tq at the wheels and that was not even being tuned. With a good tune it should give me about another 50 plus hp.

Damon · 10-01-2009, 09:44 PM

You've got a manual trans so trading away some low end torque for higher RPM horsepower isn't as bad as if you had an automatic. Autocrossing and road racing you can pretty much keep the revs up everywhere you need to in order to access the higher RPM power.

I say go for it.

But spend your money getting it tuned. And I don't just mean at WOT. Part throttle tuning is just as important- especially in an application where you are going to use part throttle around turns and such. Tuning can make or break a combo. Last thing you need is a soggy mess that goes "light switch" to max power coming out of a turn.

19doug90 · 10-06-2009, 02:29 AM

so any more opinions are welcome, i'm thinking of going with that 282 in a 110 lsa, the lsa gives me a lower rpm range (stock balanced internals, figure i'll shift around 6100-6200) and the duration gives me a bit more fill time for the largeish heads.

the motor is going in a for fun solo car seeing as how i'm not legal for any class with some of my mods, and a weekend cruiser. I realize the 110 will be a bit more effort to get a good tune on but i could care less if it has low rpm throttle response.

any reasons not to go with this cam?